Typically, image correction for correcting an input image such as a moving image or a still image is performed according to the characteristics of the input image so that a fine and conspicuous image can be output corresponding to a variety of scenes. More particularly, in the case of performing color correction of an input image by determining a color correction amount from the luminance (or brightness) of the input image, an image correcting apparatus is known that performs uniform luminance correction over the entire image by brightening dark portions and darkening bright portions. Various image correcting apparatuses have been disclosed for outputting a fine and conspicuous image corresponding to a variety of scenes.
For example, Japanese Laid-open Patent Publication No. 2003-523110 discloses an image correcting apparatus that performs, with reference to a histogram, localized adjustments in an image by brightening dark portions and darkening bright portions based on a pixel property that is a locally-measured image correction amount. Further, Japanese Laid-open Patent Publication No. 2005-318137 discloses an image correcting apparatus that splits a single image into a plurality of regions depending on the luminance, detects edges or high-frequency components in the dark portions and the bright portions in each region, and performs localized color correction.
However, in the case of implementing a conventional technology, there is occurrence of a black floating phenomenon in which the black color is perceived as the white color or a black defacement phenomenon in which a dark image becomes darker and less viewable. Besides, the implementation cost is high and it is not possible to perform high-speed processing in real time.
More particularly, while performing localized color correction as described in Japanese Laid-open Patent Publication No. 2003-523110 or Japanese Laid-open Patent Publication No. 2005-318137, a black floating phenomenon or a black defacement phenomenon occurs because it is not possible to distinguish whether, in a dark image, the dark portion falls within the range that is to be improved visually. Moreover, while performing different correction for each region as described in Japanese Laid-open Patent Publication No. 2005-318137, the processing becomes complex thereby causing an increase in the cost and making it difficult to perform high-speed processing in real time.